1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_SWAP_H 3 #define _LINUX_SWAP_H 4 5 #include <linux/spinlock.h> 6 #include <linux/linkage.h> 7 #include <linux/mmzone.h> 8 #include <linux/list.h> 9 #include <linux/memcontrol.h> 10 #include <linux/sched.h> 11 #include <linux/node.h> 12 #include <linux/fs.h> 13 #include <linux/atomic.h> 14 #include <linux/page-flags.h> 15 #include <asm/page.h> 16 17 struct notifier_block; 18 19 struct bio; 20 21 struct pagevec; 22 23 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 24 #define SWAP_FLAG_PRIO_MASK 0x7fff 25 #define SWAP_FLAG_PRIO_SHIFT 0 26 #define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */ 27 #define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */ 28 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */ 29 30 #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ 31 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ 32 SWAP_FLAG_DISCARD_PAGES) 33 #define SWAP_BATCH 64 34 35 static inline int current_is_kswapd(void) 36 { 37 return current->flags & PF_KSWAPD; 38 } 39 40 /* 41 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 42 * be swapped to. The swap type and the offset into that swap type are 43 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 44 * for the type means that the maximum number of swapcache pages is 27 bits 45 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 46 * the type/offset into the pte as 5/27 as well. 47 */ 48 #define MAX_SWAPFILES_SHIFT 5 49 50 /* 51 * Use some of the swap files numbers for other purposes. This 52 * is a convenient way to hook into the VM to trigger special 53 * actions on faults. 54 */ 55 56 /* 57 * Unaddressable device memory support. See include/linux/hmm.h and 58 * Documentation/vm/hmm.rst. Short description is we need struct pages for 59 * device memory that is unaddressable (inaccessible) by CPU, so that we can 60 * migrate part of a process memory to device memory. 61 * 62 * When a page is migrated from CPU to device, we set the CPU page table entry 63 * to a special SWP_DEVICE_* entry. 64 */ 65 #ifdef CONFIG_DEVICE_PRIVATE 66 #define SWP_DEVICE_NUM 2 67 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 68 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 69 #else 70 #define SWP_DEVICE_NUM 0 71 #endif 72 73 /* 74 * NUMA node memory migration support 75 */ 76 #ifdef CONFIG_MIGRATION 77 #define SWP_MIGRATION_NUM 2 78 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 79 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 80 #else 81 #define SWP_MIGRATION_NUM 0 82 #endif 83 84 /* 85 * Handling of hardware poisoned pages with memory corruption. 86 */ 87 #ifdef CONFIG_MEMORY_FAILURE 88 #define SWP_HWPOISON_NUM 1 89 #define SWP_HWPOISON MAX_SWAPFILES 90 #else 91 #define SWP_HWPOISON_NUM 0 92 #endif 93 94 #define MAX_SWAPFILES \ 95 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 96 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) 97 98 /* 99 * Magic header for a swap area. The first part of the union is 100 * what the swap magic looks like for the old (limited to 128MB) 101 * swap area format, the second part of the union adds - in the 102 * old reserved area - some extra information. Note that the first 103 * kilobyte is reserved for boot loader or disk label stuff... 104 * 105 * Having the magic at the end of the PAGE_SIZE makes detecting swap 106 * areas somewhat tricky on machines that support multiple page sizes. 107 * For 2.5 we'll probably want to move the magic to just beyond the 108 * bootbits... 109 */ 110 union swap_header { 111 struct { 112 char reserved[PAGE_SIZE - 10]; 113 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 114 } magic; 115 struct { 116 char bootbits[1024]; /* Space for disklabel etc. */ 117 __u32 version; 118 __u32 last_page; 119 __u32 nr_badpages; 120 unsigned char sws_uuid[16]; 121 unsigned char sws_volume[16]; 122 __u32 padding[117]; 123 __u32 badpages[1]; 124 } info; 125 }; 126 127 /* 128 * current->reclaim_state points to one of these when a task is running 129 * memory reclaim 130 */ 131 struct reclaim_state { 132 unsigned long reclaimed_slab; 133 }; 134 135 #ifdef __KERNEL__ 136 137 struct address_space; 138 struct sysinfo; 139 struct writeback_control; 140 struct zone; 141 142 /* 143 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 144 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 145 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 146 * from setup, they're handled identically. 147 * 148 * We always assume that blocks are of size PAGE_SIZE. 149 */ 150 struct swap_extent { 151 struct rb_node rb_node; 152 pgoff_t start_page; 153 pgoff_t nr_pages; 154 sector_t start_block; 155 }; 156 157 /* 158 * Max bad pages in the new format.. 159 */ 160 #define MAX_SWAP_BADPAGES \ 161 ((offsetof(union swap_header, magic.magic) - \ 162 offsetof(union swap_header, info.badpages)) / sizeof(int)) 163 164 enum { 165 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 166 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 167 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 168 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 169 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 170 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 171 SWP_BLKDEV = (1 << 6), /* its a block device */ 172 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ 173 SWP_FS = (1 << 8), /* swap file goes through fs */ 174 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 175 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 176 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 177 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 178 SWP_VALID = (1 << 13), /* swap is valid to be operated on? */ 179 /* add others here before... */ 180 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */ 181 }; 182 183 #define SWAP_CLUSTER_MAX 32UL 184 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 185 186 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 187 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 188 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 189 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 190 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 191 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 192 193 /* 194 * We use this to track usage of a cluster. A cluster is a block of swap disk 195 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 196 * free clusters are organized into a list. We fetch an entry from the list to 197 * get a free cluster. 198 * 199 * The data field stores next cluster if the cluster is free or cluster usage 200 * counter otherwise. The flags field determines if a cluster is free. This is 201 * protected by swap_info_struct.lock. 202 */ 203 struct swap_cluster_info { 204 spinlock_t lock; /* 205 * Protect swap_cluster_info fields 206 * and swap_info_struct->swap_map 207 * elements correspond to the swap 208 * cluster 209 */ 210 unsigned int data:24; 211 unsigned int flags:8; 212 }; 213 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 214 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 215 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 216 217 /* 218 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 219 * its own cluster and swapout sequentially. The purpose is to optimize swapout 220 * throughput. 221 */ 222 struct percpu_cluster { 223 struct swap_cluster_info index; /* Current cluster index */ 224 unsigned int next; /* Likely next allocation offset */ 225 }; 226 227 struct swap_cluster_list { 228 struct swap_cluster_info head; 229 struct swap_cluster_info tail; 230 }; 231 232 /* 233 * The in-memory structure used to track swap areas. 234 */ 235 struct swap_info_struct { 236 unsigned long flags; /* SWP_USED etc: see above */ 237 signed short prio; /* swap priority of this type */ 238 struct plist_node list; /* entry in swap_active_head */ 239 signed char type; /* strange name for an index */ 240 unsigned int max; /* extent of the swap_map */ 241 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 242 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 243 struct swap_cluster_list free_clusters; /* free clusters list */ 244 unsigned int lowest_bit; /* index of first free in swap_map */ 245 unsigned int highest_bit; /* index of last free in swap_map */ 246 unsigned int pages; /* total of usable pages of swap */ 247 unsigned int inuse_pages; /* number of those currently in use */ 248 unsigned int cluster_next; /* likely index for next allocation */ 249 unsigned int cluster_nr; /* countdown to next cluster search */ 250 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 251 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 252 struct block_device *bdev; /* swap device or bdev of swap file */ 253 struct file *swap_file; /* seldom referenced */ 254 unsigned int old_block_size; /* seldom referenced */ 255 #ifdef CONFIG_FRONTSWAP 256 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 257 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 258 #endif 259 spinlock_t lock; /* 260 * protect map scan related fields like 261 * swap_map, lowest_bit, highest_bit, 262 * inuse_pages, cluster_next, 263 * cluster_nr, lowest_alloc, 264 * highest_alloc, free/discard cluster 265 * list. other fields are only changed 266 * at swapon/swapoff, so are protected 267 * by swap_lock. changing flags need 268 * hold this lock and swap_lock. If 269 * both locks need hold, hold swap_lock 270 * first. 271 */ 272 spinlock_t cont_lock; /* 273 * protect swap count continuation page 274 * list. 275 */ 276 struct work_struct discard_work; /* discard worker */ 277 struct swap_cluster_list discard_clusters; /* discard clusters list */ 278 struct plist_node avail_lists[]; /* 279 * entries in swap_avail_heads, one 280 * entry per node. 281 * Must be last as the number of the 282 * array is nr_node_ids, which is not 283 * a fixed value so have to allocate 284 * dynamically. 285 * And it has to be an array so that 286 * plist_for_each_* can work. 287 */ 288 }; 289 290 #ifdef CONFIG_64BIT 291 #define SWAP_RA_ORDER_CEILING 5 292 #else 293 /* Avoid stack overflow, because we need to save part of page table */ 294 #define SWAP_RA_ORDER_CEILING 3 295 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 296 #endif 297 298 struct vma_swap_readahead { 299 unsigned short win; 300 unsigned short offset; 301 unsigned short nr_pte; 302 #ifdef CONFIG_64BIT 303 pte_t *ptes; 304 #else 305 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 306 #endif 307 }; 308 309 /* linux/mm/workingset.c */ 310 void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg); 311 void workingset_refault(struct page *page, void *shadow); 312 void workingset_activation(struct page *page); 313 314 /* Only track the nodes of mappings with shadow entries */ 315 void workingset_update_node(struct xa_node *node); 316 #define mapping_set_update(xas, mapping) do { \ 317 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \ 318 xas_set_update(xas, workingset_update_node); \ 319 } while (0) 320 321 /* linux/mm/page_alloc.c */ 322 extern unsigned long totalreserve_pages; 323 extern unsigned long nr_free_buffer_pages(void); 324 extern unsigned long nr_free_pagecache_pages(void); 325 326 /* Definition of global_zone_page_state not available yet */ 327 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 328 329 330 /* linux/mm/swap.c */ 331 extern void lru_cache_add(struct page *); 332 extern void lru_cache_add_anon(struct page *page); 333 extern void lru_cache_add_file(struct page *page); 334 extern void lru_add_page_tail(struct page *page, struct page *page_tail, 335 struct lruvec *lruvec, struct list_head *head); 336 extern void activate_page(struct page *); 337 extern void mark_page_accessed(struct page *); 338 extern void lru_add_drain(void); 339 extern void lru_add_drain_cpu(int cpu); 340 extern void lru_add_drain_all(void); 341 extern void rotate_reclaimable_page(struct page *page); 342 extern void deactivate_file_page(struct page *page); 343 extern void deactivate_page(struct page *page); 344 extern void mark_page_lazyfree(struct page *page); 345 extern void swap_setup(void); 346 347 extern void lru_cache_add_active_or_unevictable(struct page *page, 348 struct vm_area_struct *vma); 349 350 /* linux/mm/vmscan.c */ 351 extern unsigned long zone_reclaimable_pages(struct zone *zone); 352 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 353 gfp_t gfp_mask, nodemask_t *mask); 354 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); 355 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 356 unsigned long nr_pages, 357 gfp_t gfp_mask, 358 bool may_swap); 359 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 360 gfp_t gfp_mask, bool noswap, 361 pg_data_t *pgdat, 362 unsigned long *nr_scanned); 363 extern unsigned long shrink_all_memory(unsigned long nr_pages); 364 extern int vm_swappiness; 365 extern int remove_mapping(struct address_space *mapping, struct page *page); 366 extern unsigned long vm_total_pages; 367 368 extern unsigned long reclaim_pages(struct list_head *page_list); 369 #ifdef CONFIG_NUMA 370 extern int node_reclaim_mode; 371 extern int sysctl_min_unmapped_ratio; 372 extern int sysctl_min_slab_ratio; 373 #else 374 #define node_reclaim_mode 0 375 #endif 376 377 extern void check_move_unevictable_pages(struct pagevec *pvec); 378 379 extern int kswapd_run(int nid); 380 extern void kswapd_stop(int nid); 381 382 #ifdef CONFIG_SWAP 383 384 #include <linux/blk_types.h> /* for bio_end_io_t */ 385 386 /* linux/mm/page_io.c */ 387 extern int swap_readpage(struct page *page, bool do_poll); 388 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 389 extern void end_swap_bio_write(struct bio *bio); 390 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 391 bio_end_io_t end_write_func); 392 extern int swap_set_page_dirty(struct page *page); 393 394 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 395 unsigned long nr_pages, sector_t start_block); 396 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 397 sector_t *); 398 399 /* linux/mm/swap_state.c */ 400 /* One swap address space for each 64M swap space */ 401 #define SWAP_ADDRESS_SPACE_SHIFT 14 402 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 403 extern struct address_space *swapper_spaces[]; 404 #define swap_address_space(entry) \ 405 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 406 >> SWAP_ADDRESS_SPACE_SHIFT]) 407 extern unsigned long total_swapcache_pages(void); 408 extern void show_swap_cache_info(void); 409 extern int add_to_swap(struct page *page); 410 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 411 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); 412 extern void __delete_from_swap_cache(struct page *, swp_entry_t entry); 413 extern void delete_from_swap_cache(struct page *); 414 extern void free_page_and_swap_cache(struct page *); 415 extern void free_pages_and_swap_cache(struct page **, int); 416 extern struct page *lookup_swap_cache(swp_entry_t entry, 417 struct vm_area_struct *vma, 418 unsigned long addr); 419 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 420 struct vm_area_struct *vma, unsigned long addr, 421 bool do_poll); 422 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 423 struct vm_area_struct *vma, unsigned long addr, 424 bool *new_page_allocated); 425 extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 426 struct vm_fault *vmf); 427 extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, 428 struct vm_fault *vmf); 429 430 /* linux/mm/swapfile.c */ 431 extern atomic_long_t nr_swap_pages; 432 extern long total_swap_pages; 433 extern atomic_t nr_rotate_swap; 434 extern bool has_usable_swap(void); 435 436 /* Swap 50% full? Release swapcache more aggressively.. */ 437 static inline bool vm_swap_full(void) 438 { 439 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 440 } 441 442 static inline long get_nr_swap_pages(void) 443 { 444 return atomic_long_read(&nr_swap_pages); 445 } 446 447 extern void si_swapinfo(struct sysinfo *); 448 extern swp_entry_t get_swap_page(struct page *page); 449 extern void put_swap_page(struct page *page, swp_entry_t entry); 450 extern swp_entry_t get_swap_page_of_type(int); 451 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 452 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 453 extern void swap_shmem_alloc(swp_entry_t); 454 extern int swap_duplicate(swp_entry_t); 455 extern int swapcache_prepare(swp_entry_t); 456 extern void swap_free(swp_entry_t); 457 extern void swapcache_free_entries(swp_entry_t *entries, int n); 458 extern int free_swap_and_cache(swp_entry_t); 459 extern int swap_type_of(dev_t, sector_t, struct block_device **); 460 extern unsigned int count_swap_pages(int, int); 461 extern sector_t map_swap_page(struct page *, struct block_device **); 462 extern sector_t swapdev_block(int, pgoff_t); 463 extern int page_swapcount(struct page *); 464 extern int __swap_count(swp_entry_t entry); 465 extern int __swp_swapcount(swp_entry_t entry); 466 extern int swp_swapcount(swp_entry_t entry); 467 extern struct swap_info_struct *page_swap_info(struct page *); 468 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 469 extern bool reuse_swap_page(struct page *, int *); 470 extern int try_to_free_swap(struct page *); 471 struct backing_dev_info; 472 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 473 extern void exit_swap_address_space(unsigned int type); 474 extern struct swap_info_struct *get_swap_device(swp_entry_t entry); 475 476 static inline void put_swap_device(struct swap_info_struct *si) 477 { 478 rcu_read_unlock(); 479 } 480 481 #else /* CONFIG_SWAP */ 482 483 static inline int swap_readpage(struct page *page, bool do_poll) 484 { 485 return 0; 486 } 487 488 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 489 { 490 return NULL; 491 } 492 493 #define swap_address_space(entry) (NULL) 494 #define get_nr_swap_pages() 0L 495 #define total_swap_pages 0L 496 #define total_swapcache_pages() 0UL 497 #define vm_swap_full() 0 498 499 #define si_swapinfo(val) \ 500 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 501 /* only sparc can not include linux/pagemap.h in this file 502 * so leave put_page and release_pages undeclared... */ 503 #define free_page_and_swap_cache(page) \ 504 put_page(page) 505 #define free_pages_and_swap_cache(pages, nr) \ 506 release_pages((pages), (nr)); 507 508 static inline void show_swap_cache_info(void) 509 { 510 } 511 512 #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 513 #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 514 515 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 516 { 517 return 0; 518 } 519 520 static inline void swap_shmem_alloc(swp_entry_t swp) 521 { 522 } 523 524 static inline int swap_duplicate(swp_entry_t swp) 525 { 526 return 0; 527 } 528 529 static inline void swap_free(swp_entry_t swp) 530 { 531 } 532 533 static inline void put_swap_page(struct page *page, swp_entry_t swp) 534 { 535 } 536 537 static inline struct page *swap_cluster_readahead(swp_entry_t entry, 538 gfp_t gfp_mask, struct vm_fault *vmf) 539 { 540 return NULL; 541 } 542 543 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 544 struct vm_fault *vmf) 545 { 546 return NULL; 547 } 548 549 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 550 { 551 return 0; 552 } 553 554 static inline struct page *lookup_swap_cache(swp_entry_t swp, 555 struct vm_area_struct *vma, 556 unsigned long addr) 557 { 558 return NULL; 559 } 560 561 static inline int add_to_swap(struct page *page) 562 { 563 return 0; 564 } 565 566 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 567 gfp_t gfp_mask) 568 { 569 return -1; 570 } 571 572 static inline void __delete_from_swap_cache(struct page *page, 573 swp_entry_t entry) 574 { 575 } 576 577 static inline void delete_from_swap_cache(struct page *page) 578 { 579 } 580 581 static inline int page_swapcount(struct page *page) 582 { 583 return 0; 584 } 585 586 static inline int __swap_count(swp_entry_t entry) 587 { 588 return 0; 589 } 590 591 static inline int __swp_swapcount(swp_entry_t entry) 592 { 593 return 0; 594 } 595 596 static inline int swp_swapcount(swp_entry_t entry) 597 { 598 return 0; 599 } 600 601 #define reuse_swap_page(page, total_map_swapcount) \ 602 (page_trans_huge_mapcount(page, total_map_swapcount) == 1) 603 604 static inline int try_to_free_swap(struct page *page) 605 { 606 return 0; 607 } 608 609 static inline swp_entry_t get_swap_page(struct page *page) 610 { 611 swp_entry_t entry; 612 entry.val = 0; 613 return entry; 614 } 615 616 #endif /* CONFIG_SWAP */ 617 618 #ifdef CONFIG_THP_SWAP 619 extern int split_swap_cluster(swp_entry_t entry); 620 #else 621 static inline int split_swap_cluster(swp_entry_t entry) 622 { 623 return 0; 624 } 625 #endif 626 627 #ifdef CONFIG_MEMCG 628 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 629 { 630 /* Cgroup2 doesn't have per-cgroup swappiness */ 631 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 632 return vm_swappiness; 633 634 /* root ? */ 635 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 636 return vm_swappiness; 637 638 return memcg->swappiness; 639 } 640 #else 641 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 642 { 643 return vm_swappiness; 644 } 645 #endif 646 647 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 648 extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node, 649 gfp_t gfp_mask); 650 #else 651 static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, 652 int node, gfp_t gfp_mask) 653 { 654 } 655 #endif 656 657 #ifdef CONFIG_MEMCG_SWAP 658 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 659 extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 660 extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 661 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 662 extern bool mem_cgroup_swap_full(struct page *page); 663 #else 664 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 665 { 666 } 667 668 static inline int mem_cgroup_try_charge_swap(struct page *page, 669 swp_entry_t entry) 670 { 671 return 0; 672 } 673 674 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 675 unsigned int nr_pages) 676 { 677 } 678 679 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 680 { 681 return get_nr_swap_pages(); 682 } 683 684 static inline bool mem_cgroup_swap_full(struct page *page) 685 { 686 return vm_swap_full(); 687 } 688 #endif 689 690 #endif /* __KERNEL__*/ 691 #endif /* _LINUX_SWAP_H */ 692